Elastomeric materials have long been used to make shock isolator pads and launch seals for missiles. The shock isolator pads usually employ prebuckled struts to support the missile in its launch tube, provide shock mitigation, and damp vibrations. The launch seals are employed near the firing end of the missile, and must exhibit enough strength and rigidity to retain the pressure generated by the launch gases, i.e., up to about 320 lb./sq.in. at a 31/2 in. missile-launch tube gap, and not invert (flip) during launch. The launch seals must also exhibit sufficient resiliency so that they can accommodate certain axial and radial displacements of the missile, eccentricities of the launch tube and missile, and intermittent variations in the width of the annular space between the missile and the launch tube, as described by Molnar et al., in U.S. Pat. No. 4,033,593.
Tolylene diisocyanate terminated polyoxytetramethylene based prepolymers, such as Adiprene L-100 or L-167, extended with 4,4'-methylenebis (orthochloroaniline)-MOCA- have been used in the manufacture of both of these structural members, as taught by Mendelsohn et al. in I&EC Product Research & Development, Vol. 10, p. 14-25, March 1971 and Vol. 14, p. 181-189, September 1975, and by Meier et al. in Resins for Aerospace, C. A. May Editor, ACS Symposium Series 132, American Chemical Society, Chapters 14 and 15, Washington, 1980. Both the tolylene diisocyanate and the 4,4'-methylenebis (orthochloroaniline), however, are now believed to present toxicologic problems. Thus, there is a need for substitute polyurethane elastomers that can be utilized in the manufacture of shock isolator pads and launch seals that will be in circumferential contact with launchable missiles.